Abstract: An arrangement for measuring the position of a feed beam (1) in a rock drilling apparatus relative to a cradle (4) therein, or measuring the position of a rock drill (3) relative to the feed beam (1). In the arrangement an inelastic, flexible cogged belt (6; 13) is fixed to the feed beam (1) to the surface thereof, the cogged belt (6; 13) being installed to turn about the gear (9; 15) of a resolver mounted in a cradle (4) or movably with the rock drill (3), so that when the feed beam (1) moves relative to the cradle or when the rock drill (3) moves relative to the feed beam (1), the cogged belt (6; 13) rotates the gear (9; 15) of the resolver, and the resolver measures the position of the feed beam (1) or the rock drill (3) respectively.

Abstract: Electrode used for one pole in underwater transmission of high-voltage direct current, an insulated cable being used for the other pole, such electrodes being adapted to be stationary on the bottom of the sea to serve as the anode and the cathode, respectively, while the sea-water constitutes the electric conductor therebetween. What characterises the invention is that the electrode comprises at least one layer (1) of a flexible, electrically conductive material which preferably is resistant to chlorine-alkali, said layer (1) being enclosed between protective structures (2,3) of a flexible, mechanically resistant material which preferably is resistant to chlorine-alkali, at least one protective structure (2) having openings (4) which are positioned across the surface thereof and through which the sea-water comes into contact with the layer (1).

Abstract: An arrangement for handling a drilling equipment comprising clamping jaws (11a, 11b) mounted rotatably with respect to the axis of a drill tube (8a, 8b) and a breaking device (7) mounted rotatably about the axis of the drill tube (8a, 8b) and movably in the longitudinal direction of a feed beam (3), which breaking device can be connected to the drill tube (8a, 8b) or the like unrotatably with respect thereto. To move the drill tube (8a, 8b) or the like to the drilling position and away from it, respectively, the breaking device (7) is mounted turnably about an axis transverse to the longitudinal axis of the feed beam (3), which makes it possible to push the horizontal tube (8b) or the like into the breaking device (7) turned to the direction transverse to the feed beam (3) and to fasten it to the breaking device, after which the tube (8b) can be turned into a drilling center between a rotating mechanism (5) and the previous drill tube (8a) by moving the breaking device (7) along the feed beam (3).